The present invention relates to a battery charger and relates more particularly to a new battery charger device which utilizes the power supply principle and battery charging elements of the "Direct Current Power Supply Device," of U.S. patent application Ser. No. 08/128,221, filed Sep. 29, 1993. The present invention is applicable for use with either 110 V or 220 V to effectively charge any of a variety of rechargeable batteries.
The earliest D.C. (Direct Current) power supply in use is constructed using the secondary coil of a power transformer together with a full wave rectifier in connection with a voltage regulator device. Because this type of power supply tends to be heavy and bulky, it has been increasingly replaced by a high-frequency switch type of power supply. Recently, however, it has been discovered that the aforesaid switch type of power supply has defects such as serious high-frequency interference and high cost, etc. Heretofore, this problem remains as an outstanding issue without solution. In view of this, the inventor has devoted himself to developing a new battery charger device based on his research and experimentation over the years, and the present invention has been proved with success at overcoming the aforesaid problems respectively found in the two types of devices noted above. Thus, the present invention may have a significant impact on the way D.C. power supplies are used and might as well be regarded as a major advancement over the prior art.